Hand-held instruments that access interior body regions

ABSTRACT

A composite instrument is provided comprising a first functional instrument and a second functional instrument when the first functional instrument is coupled with the second functional instrument. A composite handle for the composite instrument is provided comprising a first handle and a second handle when the first handle is coupled with the second handle. The handle makes possible the reliable transmission, with increased mechanical advantage, of both torsional and longitudinal loads by the physician to the composite instrument, while resisting relative rotation between the first and second instruments.

RELATED APPLICATION

This application is a continuation-in-part of copending U.S. patentapplication Ser. No. 09/421,635, filed Oct. 19, 1999, and entitled“Hand-Held Instruments that Access Interior Body Regions,” which isincorporated herein by reference.

FIELD OF THE INVENTION

The invention generally relates to hand-held tools and instruments andto procedures that deploy these instruments through tissue to accessinterior regions of the body.

BACKGROUND OF THE INVENTION

There are many different types and styles of hand-held surgicalinstruments that physicians use to gain access into interior bodyregions. These instruments are intended to penetrate tissue by theapplication of pushing forces, twisting forces, or both in combination.

Often, a single surgical procedure will require the physician to employdifferent surgical instruments, each possessing a different shape, size,and function. Often, the procedure will require the physician to deploythese instruments in both soft and hard tissue to meet the diagnostic ortherapeutic objectives of the procedure. The physician will often needan enhanced mechanical advantage to advance an instrument throughtissue, particularly through dense or hard tissue, such as bone.

The common need to use different instruments in a given procedure,coupled with the need to accurately and reliably deploy each of thesedifferent instruments through both soft and hard tissue, often with anenhanced mechanical advantage, complicate the physician's alreadydifficult task. The need to handle different instruments in differentways for different purposes can distract the physician and lead towasted effort, which can lengthen the overall time of the procedure.

SUMMARY OF THE INVENTION

The invention provides a surgical instrument with a handle design thatallows initial placement of both a cannula and a trocar into interiorbody regions, and allows for later withdrawal of the trocar whileleaving the cannula in place. The invention obviates the need forseveral instruments during surgical procedures, and simplifies interioraccess protocol. At the same time, the handle of the surgical instrumentmakes possible the reliable transmission, with increased mechanicaladvantage, of both torsional and longitudinal loads by the physician tothe selected instrument.

One aspect of the invention provides a tool comprising a firstfunctional instrument having a first handle and a second functionalinstrument having a second handle. The first functional instrumentengages the second functional instrument, forming a compositeinstrument. The first handle mates with the second handle, forming acomposite handle for the composite instrument. The composite handleincludes a latching mechanism to resist disengagement of the first andsecond functional instruments.

Features and advantages of the inventions are set forth in the followingDescription and Drawings, as well as in the appended Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first functional instrument engaging asecond functional instrument to form a composite tool having a compositehandle that the handles of the first and second instruments form;

FIG. 2 is a perspective view of the first instrument separated from thesecond instrument;

FIG. 3 is a perspective view of a hand engaging the composite handle ofthe tool shown in FIG. 1;

FIG. 4 is a perspective view of a hand engaging the handle of the secondfunctional instrument when separated from the first functionalinstrument;

FIG. 5 is an enlarged perspective view of the handles of the first andsecond functional instruments, when separated, showing a coupling systemthan resists relative rotation between the functional instrument whenthe composite tool is formed;

FIG. 6A is an enlarged side view of the handles shown in FIG. 5, whenseparated;

FIG. 6B is an enlarged side view of the handles shown in FIG. 5, whenmated together to form the composite handle;

FIG. 6C is a side view of a trocar suited for use with the compositehandle of FIG. 6B;

FIG. 6D is a side view of a cannula suited for use with the compositehandle of FIG. 6B;

FIG. 7A is a lateral view of a human spinal column;

FIG. 7B is a coronal view, with portions broken away and in section, ofa human vertebral body, which is part of the spinal column;

FIG. 8 is a lateral view, with portions broken away and in section, ofseveral vertebral bodies, which are part of the spinal column;

FIG. 9 is a perspective view showing advancement of the compositeinstrument through tissue, by using the composite handle to supply atwisting and/or pushing force;

FIG. 10 is a top view showing deployment of the composite instrument ina vertebral body, by using the composite handle to apply an axial and/ortorsional force;

FIG. 11 is a top view of the vertebral body, showing deployment of adrill bit through a cannula instrument, which forms a part of thecomposite tool shown in FIG. 9;

FIG. 12 is a top view of the vertebral body showing deployment of anexpandable structure in a collapsed condition through the cannulainstrument that forms a part of the composite tool shown in FIG. 9;

FIG. 13 is a top view of the vertebral body after the structure shown inFIG. 12 is expanded to compact cancellous bone and form a cavity;

FIG. 14 is a top view of a syringe and attached nozzle in use to injectmaterial into the cannula instrument for passage into the cavity shownin FIG. 13;

FIG. 15 is a side view showing advancement of a tamping instrument inthe cannula instrument to displace and distribute material from thecannula instrument into the cavity shown in FIG. 13;

FIG. 16 is a side view of a syringe attached to the cannula instrumentthat forms a part of the composite tool shown in FIG. 9, for the purposeof conveying material through the cannula instrument into bone;

FIGS. 17A and 17B are perspective views showing material deformationthat occurs in each handle as a result of heat sterilization, to preventsubsequent formation of the composite handle;

FIG. 18 a perspective view of an alternative embodiment of a compositetool like that shown in FIG. 1, with an interior lumen to accommodatepassage of a spinal needle assembly to aid deployment;

FIG. 19 is a front perspective view of another embodiment of a compositetool formed by a first functional instrument engaging a secondfunctional instrument, and also having a composite handle that thehandles of the first and second instruments form;

FIG. 20 is a rear elevation view of the composite tool shown in FIG. 19;

FIG. 21 is a perspective view of the composite tool shown in FIG. 10, asthe first and second instruments are being separated;

FIG. 22 is a perspective view of the first instrument separated from thesecond instrument;

FIG. 23 is a section view of the latching mechanism for the compositetool, taken generally along line 23—23 in FIG. 20; and

FIG. 24 is a section view of the latching mechanism shown in FIG. 23,with the associated latch finger moved out of its normal latchingposition by the application of an external force.

The invention may be embodied in several forms without departing fromits spirit or essential characteristics. The scope of the invention isdefined in the appended claims, rather than in the specific descriptionpreceding them. All embodiments that fall within the meaning and rangeof equivalency of the claims are therefore intended to be embraced bythe claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This Specification describes new instruments for penetrating tissue.This specification also describes systems and methods to treat bonesusing expandable bodies in conjunction with new instruments forpenetrating tissue.

The use of expandable bodies to treat bones is generally disclosed inU.S. Pat. Nos. 4,969,888 and 5,108,404, which are incorporated herein byreference. Improvements in this regard are disclosed in U.S. patentapplication Ser. No. 08/188,224, filed Jan. 26, 1994; U.S. patentapplication Ser. No. 08/485,394, filed Jun. 7, 1995; and U.S. patentapplication Ser. No. 08/659,678, filed Jun. 5, 1996, which are eachincorporated herein by reference.

The new instruments, systems and methods will be described with regardto the treatment of vertebral bodies. It should be appreciated, however,that the handle configuration, instruments, systems and methods sodescribed are not limited in their application to vertebrae. The systemsand methods are applicable to the treatment of diverse bone types.Additionally, the handle configuration could be used with instrumentsother than a trocar and a cannula.

I. The Instruments

FIG. 1 shows a composite instrument 10 for penetrating tissue. Thecomposite instrument 10 includes a first functional instrument 20 and asecond functional instrument 40, and a composite handle 12 comprising afirst handle 22 and a second handle 42. The composite handle 12 aids aphysician in manipulating the composite instrument 10, but a physiciancan also desirably use the first handle 22 to independently manipulatethe first instrument 20 or the second handle 42 to independentlymanipulate the second instrument 40 during use.

The number and type of instruments 20 and 40 can vary. FIG. 1 shows tworepresentative instruments 20 and 40, each having a different size andfunction. In a preferred embodiment, the first functional instrument 20is a trocar instrument, and the second functional instrument 40 is acannula instrument.

A. The Trocar Instrument

Referring to FIGS. 1-4, the first instrument 20 functions as a trocarinstrument to penetrate tissue. A trocar 30 has a proximal end 32 and adistal end 34. The distal end 34 is tapered to present a penetratingsurface 35. In use, the penetrating surface 35 is intended to penetratesoft tissue and/or bone in response to pushing and/or twisting forcesapplied by the physician at the first handle 22, or the composite handle12.

The first handle 22 is coupled to the trocar 30 at the proximal end ofthe trocar 32. As best seen in FIG. 6C, the proximal end 32 of thetrocar 30 can be formed in a T-shape, with the first handle 22 beingmolded around the T-shaped end. This arrangement significantly increasesthe mechanical strength of the bond between the handle 22 and the trocar30, and allows significant longitudinal and torsional forces to betransmitted from the handle 22 to the trocar 30 without bond failure.Alternatively, with or without a T-shaped end, the proximal end 32 ofthe trocar 30 can be scored (indicated by scored region 33 in FIG. 6C)to increase the mechanical strength of the bond between the trocar 30and the handle 22, or various bonding adhesives could be used, withvarying results.

The first handle 22 desirably includes a viewing window 24, an alignmentridge receiver 26, a handle bore receiver 28, and a handle key 36, theuses of which are described later.

In an alternative embodiment (see FIG. 18), the trocar 30 includes aninterior lumen 21, which passes through the handle 22 and the body ofthe trocar 30. The interior lumen 21 accommodates passage of a styletand/or conventional spinal needle assembly 23, to guide the deploymentof the first instrument 20, by itself or nested with the secondinstrument 40 (as FIG. 18 shows), through soft tissue to a targeted bonetreatment site.

B. The Cannula Instrument

The second instrument 40 functions as a cannula instrument or guidesheath, and includes a cannula 50. The cannula 50 of the secondinstrument 40 is desirably somewhat larger in diameter than and not aslong as the trocar 30 of the first instrument 20. As best shown in FIGS.1 and 2, the second instrument 40 includes an interior lumen 44 thatextends through the instrument from its distal end 54 to its proximalend 52. The interior lumen 44 is sized to accept the trocar 30. The sizeof the interior lumen 44 desirably allows the second instrument 40 toslide and/or rotate relative to the first instrument 20, and vice versa,as will be described in greater detail later.

The distal end 54 of the second instrument 40 presents an end surface60. In use, the end surface 60 of the second instrument 40 desirablypresents a low-profile surface, which can penetrate soft tissuesurrounding the first instrument 20 in response to pushing and/ortwisting forces applied at the composite handle 12 or the second handle42.

The proximal end 52 is coupled with the second handle 42. As best seenin FIG. 6D, the proximal end 52 of the cannula 50 desirably incorporatesa flared and notched end “A” and a textured surface “B”, around whichthe second handle 42 is molded. The flared and notched end “A” andtextured surface “B” serve to increase the mechanical strength of thebond between the cannula 50 and the second handle 42, allowingsignificant longitudinal and torsional forces to be transmitted betweenthe second handle 42 and cannula 50 without bond failure. As with thetrocar 30, however, alternative bonding methods such as scoring of thecannula 50 and/or the use of various adhesives could be employed, withvarying results.

Extending from the interior lumen 44 at the proximal end 52 of thecannula 50, the second handle 42 desirably includes a handle bore 48,preferably co-circumferential with the cannula 50. The second handle 42includes an alignment ridge 46, and a handle groove 56, the uses ofwhich are described later.

C. The Drill Bit Instrument

As shown in FIG. 11, an optional third functional instrument 70functions as a drill bit. The drill bit instrument 70, having a distalend 72 and a proximal end 74, typically is slightly longer than and hasgenerally the same physical dimensions as, the trocar 30. Like thetrocar 30, the drill bit instrument 70 is intended, in use, to fit forsliding and rotational movement within the interior lumen 44 of thesecond instrument 40.

The distal end 72 of the drill bit instrument 70 desirably includescutting edges 76. In use, the cutting edges 76 are intended to penetratehard tissue in response to rotation and longitudinal load forces appliedat the proximal end 74 of the drill bit instrument 70.

The drill bit instrument 70 can be of known construction, and could varywidely. Desirably. the diameter of the drill bit instrument 70 issmaller than the interior lumen 44 of the second instrument 40, and thelength is longer than the cannula 50, such that the drill bit instrument70 can access tissue deeper than the cannula 50 when the cannula 50 isinstalled in a patient.

II. The Instrument Handles

The first handle 22 and the second handle 42 are designed to comfortablyaccommodate a hand, to desirably interlock to form a composite handle 12that resists relative rotation between the first handle 22 and thesecond handle 42, and desirably to indicate whether the instruments havebeen reused and/or resterilized.

A. Hand Accommodation

As shown in FIGS. 1-4, the composite handle 12 is shaped to becomfortably and securely grasped by a normal human hand as shown in FIG.3. Preferably, the contours of the composite handle 12 are rounded toprovide a comfortable grip and to minimize surgical glove tears.

As shown in FIG. 3, in the preferred embodiment, the first handle 22 isdesirably equipped with two finger receivers 38, intended to receive theindex finger and the pinkie finger of a physician.

Shown in FIG. 4, in the preferred embodiment, the second handle 42 isdesirably equipped with two finger receivers 58, intended to receive themiddle finger and the ring finger of a physician.

The shape and size of the first handle 22 and second handle 42, ofcourse, vary. In the embodiment shown in FIG. 1, the composite handle12, and in particular the first handle 22, includes a striking plate 14,elongated to fit comfortably across the palm of the hand. The strikingplate 14 is also configured to receive a striking blow, described later.

B. Interlocking Configuration

In order to properly interact when applying striking, pushing and/ortwisting forces to the composite handle 12, the first handle 22desirably will not rotate relative to the second handle 42. Referringnow to FIGS. 5, 6A and 6B, to avoid relative rotation, the first handle22 preferably includes the alignment ridge receiver 26 to receive thealignment ridge 46 of the second handle 42. Although described andpictured as a ridge, the alignment mechanism interaction between thefirst handle 22 and the second handle 42 could comprise any number ofshapes other than an arcuate shape, for example a block shape or a starshape.

In use, when the trocar 30 of the first instrument 20 is slid throughthe cannula 50 of the second instrument 40, the first handle 22 andsecond handle 44 can fit together to form the composite handle 12. Inaddition to the alignment ridge 46 resisting rotation because of thealignment ridge receiver 26, the first handle 22 can include a handlekey 36 for coupling with the handle groove 56 of the second handle 42.

If the handle groove 56 is not aligned with the handle key 36, and thusthe alignment ridge 46 not aligned with the alignment ridge receiver 26,the handle bore 48 of the second handle 42 desirably will not fullyinsert into the handle bore receiver 28 of the first handle 22. In thisalignment, the viewing window 24 will display the trocar 30, whichpreferably extends past the viewing window 24. Also in this alignment,the first handle 22 is desirably able to rotate independently of thesecond handle 42.

If, however, as shown in FIG. 6B, the handle groove 56 is aligned withthe handle key 36, and thus the alignment ridge 46 is aligned with thealignment ridge receiver 26, the handle bore 48 of the second handle 42can be fully inserted into the handle bore receiver 28 of the firsthandle 22.

In this operational alignment, the viewing window 24 displays the handlebore 48. Preferably, the handle bore 48 is a different color than thetrocar 30 such that visualization would be simplified. Also in thisalignment, the first handle 22 desirably does not rotate independentlyof the second handle 42. In this alignment, the composite handle 10 issized and shaped to accommodate four fingers, two fingers each on thefirst handle 22 and the second handle 42.

Of course, its should be understood that the first and second handles 22and 42 could be designed to engage in non-parallel orientations, suchthat the first and second handles 22 and 42 would not be parallel whenproperly engaged to form the composite handle 10. For example, the firsthandle 22 could incorporate a star or hexagonal shaped opening, intowhich a corresponding star or hexagonal shaped second handle 42 couldengage in a multiplicity of orientations.

In use, various forces resist relative motion between the firstinstrument 20 and the second instrument 40. As shown in FIG. 3, when ahand grips the composite handle 10, the upward force supplied by thefingers, coupled with the downward force supplied by the palm, willcompress the first instrument 20 and the second instrument 40 together.As previously noted, when properly configured, relative rotation of theinstruments is desirably constrained as well.

C. Handle Materials

1. Structural Integrity

The material chosen for the first handle 22 and the second handle 42desirably provides sufficient structural integrity to withstand manualmanipulation and forces expected from manual striking blows. The firsthandle 22 and the second handle 42 are made from a molded or cast rigidmaterial sufficient in strength to withstand the striking, pushing andtwisting forces without significant deformation.

Another preferable characteristic of the handle composition is that thefirst handle 22 and the second handle 42 can be roughened or otherwisetextured to provide a secure gripping surfaces.

2. Reuse

To encourage single use and discourage reuse and/or resterilization, itis preferable to differentiate between new hand tools and hand toolsthat have been reused and/or resterilized.

Striking and exertion of manual pressure on any of the instruments andstructures described herein during first use generates stress on thematerial or materials which make up the instruments and/or structure.The material stress created by operational loads during first use cansignificantly alter the molded morphology of the structure, makingfuture performance of the structure unpredictable.

For example, during advancement of the trocar and the cannula into thecancellous bone during a single use creates contact with surroundingcortical and cancellous bone. This contact can damage the structure,creating localized regions of weakness, which often can escape visualdetection. The existence of localized regions of weakness canunpredictably cause structural failure during a subsequent use. Suchcontact can also cause flattening and/or curling of the end surface ofthe cannula, or dulling of the penetrating surface of the trocar.

In addition, exposure to blood and tissue during a single use can entrapbiological components on or within the structure of the cannula orhandles. Despite cleaning and subsequent sterilization, the presence ofentrapped biological components can lead to unacceptable pyrogenicreactions.

As a result, following first use, the structure might not meetestablished performance and sterilization specifications. The effects ofmaterial stress and damage caused during a single use, coupled with thepossibility of pyrogen reactions even after resterilization, reasonablyjustify and encourage single use for the instruments and handles thatare deployed in tissue and bone.

To protect patients from the potential adverse consequences occasionedby multiple use, which include disease transmission, or material stressand instability, or decreased or unpredictable performance, variousmaterials may be used to indicate and possibly prevent re-use and /orresterilization of the hand tools.

For example, a heat degradable material can be used to indicate, throughdeformation, whether a hand tool has been autoclaved. Additionally,chemical sensitive pigments, such as inks commercially available fromTempil, could be applied to the composite handle 12 to indicate, througha change of color, whether a hand tool has been chemically sterilized,for instance by use of ethylene oxide (ETO), as described in therequirements of ANSI/AAMI/ISO11135:1994 for sterilizing devices. Inaddition, various materials which change color and/or physicalcomposition in the presence of other sterilization methods, such asradiation sterilization, can be incorporated into hand tools to indicatesterilization.

One material that provides sufficient structural rigidity and yetindicates whether an instrument has been exposed to heat common tosterilization is LUSTRAN™ material, which is commercially available fromBayer. As shown in FIGS. 17A and 17B, when this material is used inhandle construction, the material will typically deform during heatsterilization, desirably preventing the handle groove 56 from aligningwith the handle key 36, and thus preventing the alignment ridge 46 fromaligning with the alignment ridge receiver 26. Additionally, followingdeformation, the handle bore 48 of the second handle 42 desirably cannotbe fully inserted into the handle bore receiver 28 of the first handle22.

III. Illustrative Use of the System

The following describes use of the composite instrument 10, instruments20, 40, and 70, in conjunction with a catheter component 130, adiagnostic or therapeutic element 132, a syringe 136 and a tampinginstrument 142 as shown in FIGS. 9-15 in the context of treating bones.This is because these items can be advantageously used for this purpose.Still, it should be appreciated that the composite instrument 10 is notlimited to use in the treatment of bones, nor limited to instrumentsintended to contact tissue to perform a diagnostic or therapeuticfunction. The composite handle 12 configuration associating the firsthandle 22 and the second handle 42 can be used in association withvarious other hand-held instruments.

The composite instrument 10, handles 12, 22, and 42, and instruments 20,40, 64 and 70 will now be described with regard to the treatment ofhuman vertebra. It should be appreciated, however, their use is notlimited to human vertebrae. The handle 18 can be used in associationwith hand-held instruments in the treatment of diverse human or animalbone types.

A. Vertebral Anatomy

One use of the system is to treat vertebral bodies. As FIG. 7A shows,the spinal column 80 comprises a number of uniquely shaped bones, calledthe vertebrae 82, a sacrum 84, and a coccyx 86 (also called the tailbone). The number of vertebrae 82 that make up the spinal column 80depends upon the species of animal. In a human (which FIG. 7A shows),there are twenty-four vertebrae 82, comprising seven cervical vertebrae88, twelve thoracic vertebrae 90, and five lumbar vertebrae 92.

When viewed from the side, as FIG. 7A shows, the spinal column 80 formsan S-shaped curve. The curve serves to support the head, which is heavy.In four-footed animals, the curve of the spine is simpler.

As FIGS. 7A, 7B and 8 show, each vertebra 82 includes a vertebral body96, which extends on the anterior (i.e., front or chest) side of thevertebra 82. As FIGS. 7A, 7B and 8 show, the vertebral body 96 is in theshape of an oval disk. As FIGS. 7B and 8 show, the vertebral body 96includes an exterior formed from compact cortical bone 98. The corticalbone 98 encloses an interior volume 100 of reticulated cancellous, orspongy, bone 102 (also called medullary bone or trabecular bone). A“cushion,” called an intervertebral disk 104, is located betweenadjacent vertebral bodies 96.

An opening, called the vertebral foramen 106, is located on theposterior (i.e., back) side of each vertebra 82. The spinal ganglion 109pass through the foramen 106. The spinal cord 108 passes through thespinal canal 107.

The vertebral arch 110 surrounds the spinal canal 107. The pedicles 112of the vertebral arch 110 adjoin the vertebral body 96. The spinousprocess 114 extends from the posterior of the vertebral arch 110, as dothe left and right transverse processes 116.

B. Surgical Technique

In a typical procedure, a patient lies on an operating table, while thephysician introduces the composite instrument 10 into soft tissue(designated S in FIG. 9) in the patient's back. The patient can lie facedown on the table, or on either side, or at an oblique angle, dependingupon the physician's preference. Moreover, the procedure can beperformed through an open anterior procedure or an endoscopic anteriorprocedure.

1. Accessing Cancellous Bone

Under radiologic or CT monitoring, the physician advances the compositeinstrument 10 through soft tissue S down to and into the targetedvertebra 82, as FIG. 9 shows. The physician will typically administer alocal anesthetic, for example, lidocaine, to the targeted region. Insome cases, the physician may prefer other forms of anesthesia, such asgeneral anesthesia.

As shown in FIG. 10, the physician directs the composite instrument 10such that the trocar 30 of the first instrument 20 and the cannula 50 ofthe second instrument 40 penetrate the cortical bone 98 and thecancellous bone 102 of the targeted vertebra 82. If desired, thephysician twists the composite handle 10 while applying longitudinalforce to the handle 10. In response, the penetrating surface 35 of thetrocar 30, and the end surface 60 of the cannula 50 rotate and penetratesoft tissue and/or bone.

Preferably the depth of penetration of the distal end 34 of the trocar30 and the end surface 60 of the cannula 50 are through a first wall ofthe cortical bone 98 and into the cancellous bone 102. However, if thepenetration through the first wall of the cortical bone 98 and into thecancellous bone 102 is not achievable by manual advancement of thecomposite instrument 10, a physician can continue penetration by gentlystriking the striking plate 14 with a blunt instrument such as asurgical hammer (not shown), or otherwise applying appropriateadditional longitudinal force to the composite handle 12, to advance thedistal end 34 of the trocar 30 and the end surface 60 of the cannula 50.

If desired, the physician can utilize a spinal needle assembly andstylet to initially access the vertebral body 82, and then utilize thealternative embodiment shown in FIG. 18 to complete the accessprocedure. The embodiment shown in FIG. 18 allows the physician to placea stylet 23 into the targeted vertebral body 82, and then guide thecomposite instrument 10 through soft tissue and into the targetedvertebra body 82 along the stylet 23, which passes through the trocarlumen 21 as the composite instrument 10 is advanced through soft tissueand into the vertebral body 82. Once the trocar 30 has sufficientlypenetrated cortical bone, the physician can withdraw the spinal needleassembly 23.

After penetrating the cortical bone 98, if desired, the physician maycontinue advancing the composite instrument 10 through the cancellousbone 102 of the vertebral body 96, thereby forming a passage through thecancellous bone 102. Preferably this passage will extend no more than95% across the vertebral body. The physician may then withdraw theinstrument 10, such that the cannula 50 remains within the cortical bone98 and/or extends only part-way into the cancellous bone 102. The trocar30 may then be withdrawn from the cannula 50, allowing access to thepassage formed in the interior of the vertebral body 82 through thecannula 50.

Alternatively, after penetrating the cortical bone 98, the physician maychoose to withdraw the trocar 30 from the cannula 50 and form a passagein the cancellous bone 102 using a drill bit 70. In such a case, thephysician removes the first functional instrument 20 by holding thesecond instrument 40 in place and manually withdrawing the firstinstrument 20.

Next, as shown in FIG. 11, the physician advances the drill bit 70through the cannula 50. Under X-ray control (or using another externalvisualizing system), the physician applies appropriate twisting andlongitudinal forces to the drill bit 70, to rotate and advance thecutting edge 76 of the drill bit 70 to open a passage through the bonetissue and completely into the cancellous bone 102. The drilled passagepreferably extends no more than 95% across the vertebral body 96.

At this point in the procedure, access to the cancellous bone 102 hasbeen accomplished and the end surface 60 of the cannula 50 extends intothe interior volume 100, leaving only the cannula instrument 50 inplace.

2. Bone Treatment

As shown in FIG. 12, the physician can now acquire the cathetercomponent 130. The physician can advance the diagnostic or therapeuticelement 132 carried by the catheter component 130 through the handlebore 48 and cannula 50 and into the interior volume 100 of the vertebralbody 96.

The distal diagnostic or therapeutic element 132 of the cathetercomponent 130 can be configured to perform various functions. Forexample, the element 132 can comprise a biopsy instrument, to obtainsamples of cancellous bone or to harvest bone marrow. Alternatively, thedistal element 132 can be a stylet to introduce a medication or the likeinto cancellous bone. Still alternatively (as shown in FIG. 13), thedistal element 132 can comprise an expandable body to compact cancellousbone 102 and form a cavity 134 in the vertebral body 96, in the mannerdisclosed in U.S. Pat. Nos. 4,969,888, 5,108,404, and 5,827,289, whichare incorporated herein by reference.

Upon compaction of cancellous bone 102, the distal element 132 can alsoinclude a nozzle 140 to inject a material into the formed cavity.

Upon formation of the cavity 134, the physician acquires a syringe 136and injection nozzle 140. As FIG. 14 shows, the nozzle 140 is sized topass through the cannula 50, to thereby pass into the cavity 134. Thenozzle 140 connects by a threaded connector 186 to a syringe 136. Thenozzle 140 can be formed from a rigid metal material, e.g., stainlesssteel.

As FIG. 14 shows, the physician fills the syringe 136 with the desiredvolume of filling material 138. The physician attaches the nozzle 140 tothe filled syringe 136. The physician inserts the nozzle 140 a selecteddistance beyond the distal end 54 of the cannula 50 and into the cavity,guided by markings 166 on the nozzle 140. Next, the physician operatesthe syringe 136 to expel the material 138 through the nozzle 140 intothe cavity 134.

Desirably, the physician first introduces the material 138 into theregion of the cavity 134 farthest from the distal end 54 of the cannula54. The physician successively draws the nozzle 140 toward the distalend 54 of the cannula 50, while injecting the material 138, to fill theremainder of the cavity 54.

At this stage, the nozzle 180 is unthreaded from the syringe 104. AsFIG. 15 shows, the physician next advances a tamping instrument 142through the nozzle 140. The distal end of the tamping instrument 142contacts the residual volume of material 138 in the nozzle 140.Advancement of the tamping instrument 142 displaces the residualmaterial 138 from the nozzle 140, forcing it into the cavity 134. Theflow of material 138 into the cavity 134, propelled by the advancementof the tamping instrument 142 in the nozzle 140 serves to uniformlydistribute and compact the material 138 inside the cavity 134, withoutthe application of undue pressure.

As shown in FIG. 16, as an alternative to attaching the nozzle 140 tothe syringe 136, the physician can attach the syringe 136 directly tothe handle bore 48 of the second instrument 40. As shown in thealternate embodiment in FIG. 16, the syringe 136 can have threads 137 orother fasteners, such as snap-sit fasteners or luer-lock fasteners. Thethreads 137 would match with bore threads 49 contained in the handlebore 48. Next, the physician operates the syringe 136 to expel thematerial 138 through the handle bore 48 and the cannula 50 and directlyinto the cavity 134. In this arrangement, the physician disconnects thesyringe 136 and advances the tamping instrument 142 through the handlebore 48 and the cannula 50 to displace the residual material 138 fromthe cannula 50, forcing it into the cavity 134.

The use of the syringe 136 with or without nozzle 140, and the tampinginstrument 142 allows the physician to exert precise control whenfilling the cavity 134 with material 138. The physician can immediatelyadjust the volume and rate of delivery according to the particular localphysiological conditions encountered. The application of low pressure(i.e., desirably no greater than 360 psi at the distal end of thecannula, more desirably no greater that 190 psi at the distal end of thecannula, and most desirably no greater than 100 psi at the distal end ofthe cannula), which is uniformly applied by the tamping instrument 142,allows the physician to respond to fill volume, flow resistance, andflow path conditions quickly. The chance of overfilling and leakage ofmaterial 138 outside the cavity portion is thereby significantlyreduced.

When the physician is satisfied that the material 138 has been amplydistributed inside the cavity portion, the physician withdraws thetamping instrument 142 from the cannula 50 and handle bore 48. Thephysician preferably first twists the tamping instrument 142 to cleanlybreak contact with the material 138.

Of course, this procedure could be repeated to access and treat onevertebral body multiple times in multiple orientations to createmultiple cavities that may or may not interconnect. After a cavity hasbeen filled and tamped in the above described manner, the instrumentscan be withdrawn and the incision sites sutured closed. The bonetreatment procedure is concluded.

C. Suggested Materials

Desirably, the material 138 will provide sufficient support within thevertebral body to prevent further fracture of the body. The capabilityof the vertebral bodies to withstand loads will have thereby beenimproved. The material may also facilitate healing of the vertebralbody.

The selected material 138 can be a bone cement, or autograft orallograft bone graft tissue collected in conventional ways, e.g., inpaste form (see Dick, “A Use of the Acetabular Reamer to HarvestAutogenic Bone Graft Material: A Simple Method for Producing BonePaste,” Archives of Orthooaedic and Traumatic Surgery (1986), 105:235-238), or in pellet form (see Bhan et al, “A Percutaneous BoneGrafting for Nonunion and Delayed Union of Fractures of the TibialShaft,”@ International Orthopaedics (SICOT) (1993) 17: 310-312).Alternatively, the bone graft tissue can be obtained using a Bone GraftHarvester, which is commercially available from SpineTech. Using afunnel, the paste or pellet graft tissue material is loaded into thecannula 50. The tamping instrument 142 is then advanced into the cannula50 in the manner previously described, to displace the paste or pelletgraft tissue material out of the cannula 50 and into the cavity 134.

The selected material 138 can also comprise a granular bone materialharvested from coral, e.g., ProOsteon™ calcium carbonate granules,available from Interpore. The granules are loaded into the cannula 50using a funnel and advanced into the cavity using the tamping instrument142.

The selected material 138 can also comprise demineralized bone matrixsuspended in glycerol (e.g., Grafton™ allograft material available fromOsteotech), or SRS™ calcium phosphate cement available from Novian.These viscous materials, like the bone cement previously described, canbe loaded into the syringe 136 and injected into the cavity directly orusing the nozzle 140, which is inserted through the cannula 50 into thecavity 134. The tamping instrument 142 is used to displace residualmaterial from the cannula 50 into the cavity 134, as before described.

The selected material 138 can also be in sheet form, e.g. Collagraft™material made from calcium carbonate powder and collagen from bovinebone. The sheet can be rolled into a tube and loaded by hand into thecannula 50. The tamping instrument 142 is then advanced through thecannula 50, to push and compact the material in the cavity 134.

IV. Interlocking Hand Held Instruments

FIGS. 19 and 20 show an alternative embodiment for a compositeinstrument 210 for penetrating tissue, which shares many of the featuresof the composite instrument 10, previously described. As FIG. 22 shows,when disassembled, the composite instrument 210, like the compositeinstrument 10 previously described, includes a first functionalinstrument 220 and a second functional instrument 240. A compositehandle 212 joins the two instruments 220 and 240, when assembled (asFIGS. 19 and 20 show). The composite handle 212 comprises a first handle222 (associated with the first instrument 220) and a second handle 242(associated with the second instrument 240) (as FIG. 22 also shows).Like the composite handle 12 for the composite instrument 10, thecomposite handle 212 for the instrument 210 aids a physician inmanipulating the composite instrument 210, but a physician can alsodesirably use the first handle 222 to independently manipulate the firstinstrument 220 or the second handle 242 to independently manipulate thesecond instrument 240 during use.

As previously explained, the number and type of instruments 220 and 240can, of course, vary. In the illustrated embodiment, each instrument 220and 240 has a different size and function. In a preferred embodiment,the first functional instrument 220 is a trocar instrument, and thesecond functional instrument 240 is a cannula instrument.

A. The Trocar Instrument

Referring to FIG. 22, the first instrument 220 functions as a trocarinstrument 230 to penetrate tissue. The trocar 230 has a proximal end232 and a distal end 234. The distal end 234 is intended to penetratesoft tissue and/or bone in response to pushing and/or twisting forcesapplied by the physician at the first handle 222, or the compositehandle 212. If desired, the distal end 234 can terminate in asubstantially blunt and/or cannulated tip, or alternatively terminate ina sharpened tip for cutting through tissue, as known in the art.

The first handle 222 is coupled to proximal end 232 of the trocar 230.Similar to that shown in FIG. 6C for the trocar 30, the proximal end 232of the trocar 230 can likewise be formed in a T-shape, with the firsthandle 222 being molded around the T-shaped end. As earlier describedwith reference to the trocar 30, this arrangement significantlyincreases the mechanical strength of the bond between the handle 222 andthe trocar 230, and allows significant longitudinal and torsional forcesto be transmitted from the handle 222 to the trocar 230 without bondfailure. Alternatively, with or without a T-shaped end, the proximal end232 of the trocar 230 can be scored (as shown, in relation to the trocar32, by scored region 33 in FIG. 6C) to increase the mechanical strengthof the bond between the trocar 230 and the handle 222, or variousbonding adhesives could be used, with varying results.

The first handle 222 desirably includes a receiving channel 226 with aviewing window 224 and a latch mechanism 236 (also shown in FIGS. 23 and24), the structure and function of which are described later.

Like the trocar 30, the trocar 230 may include an interior lumen (notshown), which passes through the handle 222 and the body of the trocar230, to accommodate passage of a stylet and/or conventional spinalneedle assembly, to guide the deployment of the first instrument 220, byitself or nested with the second instrument 240 (as FIG. 18 shows withrespect to the first described embodiment) , through soft tissue to atargeted bone treatment site.

B. The Cannula Instrument

Still referring principally to FIG. 22, the second instrument 240functions as a cannula instrument or guide sheath, and includes acannula 250. The cannula 250 of the second instrument 240 is desirablysomewhat larger in diameter than and not as long as the trocar 230 ofthe first instrument 220. As best shown in FIG. 21, the secondinstrument 240 includes an interior lumen 244 that extends through theinstrument from its distal end 254 to its proximal end 252. The interiorlumen 244 is sized to accept the trocar 230 (as FIG. 21 shows). The sizeof the interior lumen 244 desirably allows the second instrument 240 toslide and/or rotate relative to the first instrument 220, and viceversa, unless the two handles 222 and 242 are locked together, as willbe described later.

The distal end 254 of the second instrument 240 presents an end surfacethat desirably presents a low-profile surface, which can penetrate softtissue surrounding the first instrument 220 in response to pushingand/or twisting forces applied at the composite handle 212 or the secondhandle 242.

The proximal end 252 is coupled with the second handle 242. As shown inFIG. 6D with respect to the cannula 50, the proximal end 252 of thecannula 250 can desirably incorporate a flared and notched end “A”and/or a textured surface “B”, around which the second handle 242 ismolded. The flared and notched end “A” and/or textured surface “B” serveto increase the mechanical strength of the bond between the cannula 250and the second handle 242, allowing significant longitudinal andtorsional forces to be transmitted between the second handle 242 andcannula 250 without bond failure. As with the trocar 230, however, otherbonding methods such as scoring of the cannula 250 and/or the use ofvarious adhesives could be employed, with varying results.

Extending from the interior lumen 244 at the proximal end 252 of thecannula 250, the second handle 242 desirably includes a handle bore 248,preferably co-circumferential with the cannula 250. The second handle242 includes a transverse shoulder 246 and at least one latch notch 256on the shoulder 246, the structure and function of which are describedlater.

C. The Handles

The first handle 222 and the second handle 242 are designed tocomfortably accommodate a hand, to desirably interlock to form acomposite handle 212 that resists relative rotation between the firsthandle 222 and the second handle 242.

D. Hand Accommodation

Like the composite handle 12, the composite handle 212 is shaped to becomfortably and securely grasped by a normal human hand, as generallyshown in FIG. 21. Preferably, the contours of the composite handle 212are likewise rounded to provide a comfortable grip and to minimizesurgical glove tears. The first handle 222 is desirably equipped withtwo finger receivers 238, intended to receive the index finger and thepinkie finger of a physician, in the same fashion shown for the handle12 in FIG. 3.

The second handle 242 is desirably equipped with two finger receivers258, intended to receive the middle finger and the ring finger of aphysician, in the same fashion shown for the handle 42 in FIG. 4.

The shape and size of the first handle 222 and second handle 242, ofcourse, vary. In the embodiment shown in FIGS. 19 to 21, the compositehandle 212, and in particular the first handle 222, includes a strikingplate 214, elongated to fit comfortably across the palm of the hand. Thestriking plate 214 is also configured to receive a striking blow, forthe purposes described above.

The material chosen for the first handle 222 and the second handle 242desirably provides sufficient structural integrity to withstand manualmanipulation and forces expected from manual striking blows. The firsthandle 222 and the second handle 242 are made from a molded or castrigid material sufficient in strength to withstand the striking, pushingand twisting forces without significant deformation. Representativematerials for the first and second handles 222 and 242 can includevarious plastics, metals, and/or ceramics well known in the art. In onedisclosed embodiment, the first and second handles 222 and 242 areformed from Lustran® ABS (acrylonitrile-butadiene-styrene) plastic,available commercially from Bayer Corporation.

Another preferable characteristic of the handle composition is that thefirst handle 222 and the second handle 242 can be roughened or otherwisetextured to provide a secure gripping surfaces.

E. Interlocking Configuration

In order to properly interact when applying striking, pushing and/ortwisting forces to the composite handle 212, the first handle 222desirably will not rotate relative to the second handle 242 when the twohandles 222 and 242 are secured together. To avoid relative rotation,the first handle 222 preferably includes the receiving channel 226 intowhich the shoulder 246 of the second handle 242 is advanced and nests(see FIGS. 23 and 24)

In use, when the trocar 230 of the first instrument 220 is slid throughthe cannula 250 of the second instrument 240 (see FIG. 21), the firsthandle 222 and second handle 244 fit together to form the compositehandle 212 (as FIG. 19 shows). The shoulder 246 nests within the lockingchannel 226, resisting rotation of the first instrument 220 relative tothe second instrument 240.

Furthermore, when the locking shoulder 246 is advanced a desireddistance through the channel 226, the latch mechanism 236 on the firsthandle 222 engages the latch notch 256 on the second handle 242, toresist separation of the two instruments 220 and 240.

The latch mechanism 236 can be constructed in various ways. As shown inFIGS. 23 and 24, the latch mechanism 236 includes a latch finger 260situated to engage the latch notch 256 on the second handle 242. Thelatch finger 260 is carried on a hinge 262 in the first handle 222. Thehinge 262 is desirably made from resilient plastic material andpossesses plastic memory, forming a so-called “living hinge.”

The latch finger 260 is cantilevered on the hinge 262 for pivotingmovement within the first handle 222. The plastic memory of the hinge262 normally biases the finger 260 toward a normal position, shown inFIG. 23, in which the finger 260 will rest within the notch 256,provided that the two parts are in alignment. The latch finger 260 canbe displaced out of its normal position (as shown in FIG. 24) inresponse to an applied force F. Upon removal of the force F, the hinge262 returns the finger 260 to its normal position.

In the illustrated embodiment, the force F is applied in at least twodifferent ways. One works in response to advancement of the shoulder 246through the channel 226 toward the latch mechanism 236. This serves tosecure the two instruments 220 and 240 together, for use as a compositeinstrument 210. The other works in response to manual pressure exertedby an operator upon the latch mechanism 236. This serves to separate thetwo instruments 220 and 240, for use of the instruments 220 and 240individually.

Regarding the first mechanism, the latch finger 260 includes a camsurface 264 (best shown in FIG. 24). The leading edge 266 of the lockingshoulder 246 slides or rides along the cam surface 264 as the shoulder246 progresses through the channel 226. Progressive advancement of theleading edge 266 of the shoulder 246 along the cam surface 264 willapply the force F, to cause the latch finger 260 to pivot on the hinge262. When the locking notch 256 on the shoulder 246 is in mutualalignment with the latch finger 260, the force F is relieved, and thelatch finger 260 resiliently returns toward its normal position. Thismoves the latch finger 260 into the notch 256, in a snap-fit. Theplastic memory of the hinge resists movement of the notch 256 out ofengagement with the latch finger 260, effectively locking the twohandles 222 and 242 together as the composite handle 212.

The shoulder 246 desirably includes a locking notch 256 on reversefacing, opposite sides of the shoulder 246. In this way, the fitment ofthe shoulder 246 into the channel 226 is not sensitive to mutualorientation of the two handles 222 and 242.

The viewing window 224 on the first handle 222 reveals the advancementof the shoulder 246 through the channel 226 and into engagement with thelatching mechanism 236. This provides visual confirmation of the lockingfit. Preferably, the shoulder 246 is a different color than first handle220, such that visualization would be further simplified.

When formed, the composite handle 210 is sized and shaped to accommodatefour fingers, two fingers each on the first handle 222 and the secondhandle 242, in the same fashion shown for the composite handle 10 inFIG. 3.

Regarding the second mechanism for applying the force F to the latchfinger 260, the latch mechanism 236 also includes a detent surface 268.Pressing against the detent surface 268 applies the force F to the latchfinger 260, causing the finger 260 to pivot on the hinge 262. The latchmechanism 236 also desirably incorporates a stop 280, which limits thedisplacement of the latch mechanism during release. The force F freesthe finger 260 from the notch 256, to allow the shoulder 246 to bewithdrawn from the channel 226. The operator can thereby separate thetwo handles 222 and 224 (as FIG. 21 shows).

The composite instrument 210 and the instruments 220 and 240 can be usedin conjunction with a catheter element 130, a diagnostic or therapeuticelement 132, and other instruments in the same fashion as the compositeinstrument 10, previously described.

The disclosed composite instrument 210 also greatly facilitatesmanipulation and use of the instrument by a physician wearing leadedand/or lead-lined gloves during the surgical procedure. Because manyprocedures are performed under fluoroscopic visualization, physiciansrepeatedly performing these procedures often wear leaded gloves tominimize exposure of their hands to harmful radiation. Such gloves areoften thick, uncomfortable, and incorporate radiopaque materials, suchas lead, and typically negatively impact the ability of the surgeon tomanipulate small objects or to “feel” the surgical instruments duringthe procedure. With the disclosed composite instrument 210, thephysician can hold the instrument in a single hand, and can use a singlefinger to depress the detent surface 268 to separate the two handles 222and 242. The detent surface 268 is desirably sized such that it can beeasily felt and manipulated, even through leaded gloves.

Moreover, because the stop 280 desirably limits the displacement of thelatch mechanism 236 during release, the latch mechanism 236 canwithstand a significant amount of force F without damage to the hinge262. This is especially important where the physician is wearing leadedgloves, because the physician may not be able to accurately gage theamount of force he or she is imparting to a given tool. Even where thephysician uses an excessive amount of force to release the instrument,therefore, the disclosed composite instrument 210 is less likely to failduring the surgical procedure.

The features of the invention are set forth in the following claims.

We claim:
 1. A tool comprising: a first functional instrument includinga first handle, the first handle including a first distal fingergripping surface and a first proximal finger gripping surface, a secondfunctional instrument including a second handle, the second handleincluding a second distal finger gripping surface and a second proximalfinger gripping surface, the first functional instrument engaging thesecond functional instrument, forming a composite instrument, and thefirst handle mating with the second handle when the first functionalinstrument is engaged with the second instrument forming a compositehandle, whereby the first distal gripping surface and the second distalgripping surface fit together to form a composite finger grippingsurface that includes the first distal gripping surface and the seconddistal gripping surface.
 2. A tool according to claim 1, wherein thefirst functional instrument is a trocar instrument.
 3. A tool accordingto claim 1, wherein the second functional instrument is a cannulainstrument.
 4. A tool according to claim 1 wherein the composite handleis adapted, in use, to transmit longitudinal force to the compositeinstrument.
 5. A tool according to claim 1 wherein the composite handleis adapted, in use, to transmit rotational force to the compositeinstrument.
 6. A tool according to claim 1 wherein the composite handleis adapted, in use, to transmit both longitudinal and rotational forcesto the composite instrument.
 7. A tool according to claim 1, wherein thecomposite handle is adapted, in use, to receive a striking force.
 8. Atool according to claim 1, wherein the composite handle is constructedof material capable of resisting deformation when a striking force isapplied.
 9. A tool according to claim 1, wherein the second functionalinstrument is a cannula, and the first functional instrument is a trocarsized for passage through the cannula.
 10. A tool according to claim 9,wherein the trocar is longer than the cannula.
 11. A tool according toclaim 1 wherein the first gripping surface includes two adjacent fingerreceivers, and wherein the second gripping surface includes twospaced-apart finger receivers, and wherein the two adjacent fingerreceivers fit between the two spaced-apart finger receivers to providean array of adjacent finger receivers that form the composite grippingsurface.
 12. A tool according to claim 1 wherein the composite handleincludes a latching mechanism to resist disengagement of the first andsecond functional instruments.
 13. A method of manipulating aninstrument that, in use, accesses bone comprising the steps of providinga first functional instrument including a first handle, the first handleincluding a first distal finger gripping surface and a first proximalfinger gripping surface, providing a second functional instrumentincluding a second handle, the second handle including a second distalfinger gripping surface and a second proximal finger gripping surface,engaging the second functional instrument with the first functionalinstrument to form a composite instrument, and mating the first handlewith the second handle when the first functional instrument is engagedwith the second instrument to form a composite handle in which the firstdistal gripping surface and the second distal gripping surface fittogether to form a composite finger gripping surface that includes thefirst distal gripping surface and the second distal gripping surface,and manipulating the composite instrument while gripping the compositefinger gripping surface.
 14. A tool comprising: a first functionalinstrument including a first handle, the first handle including a firstfinger gripping surface including two adjacent finger receivers, asecond functional instrument including a second handle, the secondhandle including a second finger gripping surface including twospaced-apart finger receivers, the first functional instrument engagingthe second functional instrument, forming a composite instrument, andthe first handle mating with the second handle when the first functionalinstrument is engaged with the second instrument forming a compositehandle, whereby the two adjacent finger receivers of the first grippingsurface fit between the two spaced-apart finger receivers of the secondgripping surface to provide an array of adjacent finger receivers thatform a composite finger gripping surface that includes the first andsecond finger gripping surfaces.
 15. A tool comprising: a firstfunctional instrument including a first handle, the first handleincluding a first finger gripping surface, a second functionalinstrument including a second handle, the second handle including asecond finger gripping surface, the first functional instrument engagingthe second functional instrument, forming a composite instrument, andthe first handle mating with the second handle when the first functionalinstrument is engaged with the second instrument forming a compositehandle, whereby the first gripping surface and the second grippingsurface fit together to form a composite finger gripping surface thatincludes the first and second finger gripping surfaces, the compositehandle including a latching mechanism to resist disengagement of thefirst and second functional instruments.